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Message-ID: <272ca19e-749e-92fb-bcfa-ca695b3b9ed6@collabora.com>
Date: Tue, 30 Nov 2021 11:39:22 +0100
From: Andrzej Pietrasiewicz <andrzej.p@...labora.com>
To: Ezequiel Garcia <ezequiel@...guardiasur.com.ar>,
Jernej Škrabec <jernej.skrabec@...il.com>
Cc: Dan Carpenter <dan.carpenter@...cle.com>,
linux-media <linux-media@...r.kernel.org>,
Nicolas Dufresne <nicolas.dufresne@...labora.com>,
Mauro Carvalho Chehab <mchehab@...nel.org>,
Rob Herring <robh+dt@...nel.org>,
Maxime Ripard <mripard@...nel.org>,
Chen-Yu Tsai <wens@...e.org>,
Philipp Zabel <p.zabel@...gutronix.de>,
Greg KH <gregkh@...uxfoundation.org>,
devicetree <devicetree@...r.kernel.org>,
linux-arm-kernel <linux-arm-kernel@...ts.infradead.org>,
linux-sunxi@...ts.linux.dev,
Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
"open list:STAGING SUBSYSTEM" <linux-staging@...ts.linux.dev>,
Robert Beckett <bob.beckett@...labora.com>
Subject: Re: [PATCH 1/7] media: hantro: add support for reset lines
Hi Ezequiel,
W dniu 23.11.2021 o 19:07, Ezequiel Garcia pisze:
> Hi all,
>
> Reset logic tends to be highly integration-specific, so it could be more robust
> to deal with this in the machine specific file. I have some vague recollection
> of our experience here when we integrated vc8000 last year, but I cannot recall
> the outcome.
>
Do you mean vpu->variant->init()?
That is the very first thing we do after the devm_*() calls. So any subsequent
initialization that fails would want vpu->variant->deinit(). Maybe at this
moment handling the resets at the common level is simpler? Existing drivers
will get NULL anyway from devm_reset_control_array_get().
Regards,
Andrzej
> I'm Ccing Bob who might remember better.
>
> Thanks,
> Ezequiel
>
>
>
> El mar., nov. 23, 2021 1:46 PM, Jernej Škrabec <jernej.skrabec@...il.com
> <mailto:jernej.skrabec@...il.com>> escribió:
>
> Hi all,
>
> Dne torek, 23. november 2021 ob 17:36:57 CET je Andrzej Pietrasiewicz
> napisal(a):
> > Hi Dan, hi Jernej,
> >
> > W dniu 23.11.2021 o 15:59, Dan Carpenter pisze:
> > > On Tue, Nov 23, 2021 at 12:09:03PM +0100, Andrzej Pietrasiewicz wrote:
> > >>> diff --git a/drivers/staging/media/hantro/hantro_drv.c b/drivers/staging/
> media/hantro/hantro_drv.c
> > >>> index ab2467998d29..8c3de31f51b3 100644
> > >>> --- a/drivers/staging/media/hantro/hantro_drv.c
> > >>> +++ b/drivers/staging/media/hantro/hantro_drv.c
> > >>> @@ -905,6 +905,10 @@ static int hantro_probe(struct platform_device
> *pdev)
> > >>> return PTR_ERR(vpu->clocks[0].clk);
> > >>> }
> > >>> + vpu->resets = devm_reset_control_array_get(&pdev->dev, false,
> true);
> > >>> + if (IS_ERR(vpu->resets))
> > >>> + return PTR_ERR(vpu->resets);
> > >>> +
> > >>> num_bases = vpu->variant->num_regs ?: 1;
> > >>> vpu->reg_bases = devm_kcalloc(&pdev->dev, num_bases,
> > >>> sizeof(*vpu->reg_bases),
> GFP_KERNEL);
> > >>> @@ -978,10 +982,16 @@ static int hantro_probe(struct platform_device
> *pdev)
> > >>> pm_runtime_use_autosuspend(vpu->dev);
> > >>> pm_runtime_enable(vpu->dev);
> > > ^^^^^^^^^^^^^^^^^^^^^^^^^^^
> > > It looks like this is the pm stuff that we have to unwind on error
> > >
> > >>> + ret = reset_control_deassert(vpu->resets);
> > >>> + if (ret) {
> > >>> + dev_err(&pdev->dev, "Failed to deassert resets\n");
> > >>> + return ret;
> > > ^^^^^^^^^^
> > > So this return should be a goto undo_pm_stuff
> > >
> > >
> > >>> + }
> > >>> +
> > >>> ret = clk_bulk_prepare(vpu->variant->num_clocks, vpu->clocks);
> > >>> if (ret) {
> > >>> dev_err(&pdev->dev, "Failed to prepare clocks\n");
> > >>> - return ret;
> > >
> > > And this return should also have been a goto so it's a bug in the
> > > original code.
> >
> > So we probably want a separate patch addressing that first, and then
> > the series proper on top of that.
>
> I was just about to suggest that.
>
> Other drivers usually enable PM last, so they don't have PM calls in unwind
> code. However, I think current approach is just as valid (with a fix).
>
> Best regards,
> Jernej
>
> >
> > Regards,
> >
> > Andrzej
> >
> > >
> > >>> + goto err_rst_assert;
> > >>
> > >> Before your patch is applied if clk_bulk_prepare() fails, we
> > >> simply return on the spot. After the patch is applied not only
> > >> do you...
> > >>
> > >>> }
> > >>> ret = v4l2_device_register(&pdev->dev, &vpu->v4l2_dev);
> > >>> @@ -1037,6 +1047,8 @@ static int hantro_probe(struct platform_device
> *pdev)
> > >>> v4l2_device_unregister(&vpu->v4l2_dev);
> > >>> err_clk_unprepare:
> > >>> clk_bulk_unprepare(vpu->variant->num_clocks, vpu->clocks);
> > >>> +err_rst_assert:
> > >>> + reset_control_assert(vpu->resets);
> > >>
> > >> ...revert the effect of reset_control_deassert(), you also...
> > >>
> > >>> pm_runtime_dont_use_autosuspend(vpu->dev);
> > >>> pm_runtime_disable(vpu->dev);
> > >>
> > >> ... do pm_*() stuff. Is there any reason why this is needed?
> > >
> > > So, yes, it's needed, but you're correct to spot that it's not
> > > consistent.
> > >
> > > regards,
> > > dan carpenter
> > >
> >
> >
>
>
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